Also, wouldn't there be two different jumps?

Josheir

fleabay, You were so right! Thanks a million! here is the working code:

window.setKeyRepeatEnabled(false);
	while (window.isOpen())
	{
		sf::Clock clock;
		sf::Event event;
		while (window.pollEvent(event))
		{
			if (event.type == sf::Event::Closed)
				window.close();

			///////////jump/scroll//////////
			//if (sf::Keyboard::isKeyPressed(sf::Keyboard::J))
			else if (event.type == sf::Event::KeyPressed) {
				if (event.key.code == sf::Keyboard::J) {

					character.JumpInEndZone(line, SCREENWIDTH, SCREENHEIGHT, character, vectorPlatforms, positionX, positionY, velocityY, velocityX,
						gravity, isLeft, window, marioSpriteR, marioSpriteL, goingDown, characterOnBar);


				}
			}
		}
	}

A bit too late for the party, but this dynamic behavior stuff can be debugged nicely by injecting a few print statements in the code at relevant places.

Here it would be at the spot where you start the jump. If you have that output next to the graphic display, you can easily see how often such relevant spots are visited, but also, at which point in time. The latter usually provides useful hints for where to search for the bug.

Thanks everyone, some real good help! My jump function has a while, but because I want variable jumping and the ability to control the horizontal aspect a bit I need to jump one step than check for ongoing keypresses. I was thinking of using a counter, and for example, every fourth run change the jump.

Josheir